A complex project not to be underestimated: what’s really involved in installing a wall-mounted heat pump
At AirGreen, we often get questions from homeowners who are considering doing their own wall-mounted heat pump installation. Whether it’s to save on labor costs or to take on a personal technical challenge, the idea can seem appealing. But in reality, this type of project is far more complicated than it looks. From electrical considerations, refrigerant handling risks, to compliance with the Quebec Building Code, and the importance of preserving manufacturer warranties, installing a wall-mounted heat pump yourself carries serious risks.
We’re sharing everything you need to know before diving in, based on our direct experience with hundreds of wall-mounted heat pump installations in Montréal, Laval, Longueuil, the North Shore, and the South Shore.
Understanding how a wall-mounted heat pump works
Before thinking about installing one, you should know that a wall-mounted heat pump is a complex HVAC system that acts as both an air conditioner and a heating unit. It runs on a thermodynamic cycle using refrigerant fluid (R-410A, R-32, R-454B, etc.) to transfer heat from one place to another. This fluid travels through a sealed circuit that connects the indoor unit to the outdoor unit. The quality of this installation is crucial to ensure performance, energy efficiency, and the longevity of the system.
Wall-mounted installation: more than just drilling a few holes
Installing a wall-mounted heat pump involves far more than just mounting the indoor unit on a wall. Here are some critical steps we carry out during every professional installation:
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Thermal assessment of the space (correct BTU sizing based on the room’s square footage).
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Optimal unit placement to avoid energy loss and noise issues.
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Drilling through the exterior wall precisely to run the refrigerant lines, condensation drain, and electrical cables.
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Mounting the outdoor wall bracket and installing the outdoor unit with exact leveling.
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Connecting refrigerant lines with precise bending and nitrogen-purged brazing, followed by pressure testing using dry nitrogen.
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Vacuum pulling using a dedicated pump to remove moisture and air before opening the circuit.
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Electrical wiring on a dedicated breaker, usually performed by a certified electrician.
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Startup and full system testing.
Each of these steps comes with significant risks if done improperly.
Risks associated with DIY installation
Non-compliance with code
HVAC installations must meet strict provincial requirements in Quebec, particularly the Construction Code. If you ever decide to sell your property, a non-compliant installation can result in major correction costs or even delay a real estate transaction.
Safety hazards
Incorrect electrical wiring can cause short circuits, fire hazards, or damage to the system. Improper refrigerant handling can lead to toxic leaks or release harmful gases into the environment.
Voided manufacturer warranty
Wall-mounted heat pump manufacturers like Fujitsu, Gree, Sharp, Bosch, or Tosot require certified professionals for installation. A DIY job will void any 5-, 10-, or even 12-year warranty on parts and labor.
Poor performance
A poorly installed system will lead to lower efficiency, unusual noise, premature compressor failure, and higher energy bills. That defeats the entire purpose of having a heat pump—to enjoy comfort and savings.
AirGreen’s on-the-ground expertise: real case studies
In Boisbriand, on the North Shore, we recently corrected a DIY installation of a Gree Lomo 12,000 BTU heat pump. The homeowner skipped the proper vacuum process. The result: the compressor failed in less than a year. We had to replace the outdoor unit and bring the entire setup up to code—an expensive fix.
In Longueuil, a client attempted to install a Fujitsu 15RL2 wall-mounted heat pump. The indoor mounting wasn’t anchored properly into the drywall, and the unit fell off the wall after a few days. Fortunately, no one was injured, but the indoor unit was beyond repair.
Required tools and certifications
Professional installation requires:
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A valid refrigeration certification (TQ).
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A valid RBQ license.
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Specialized tools: vacuum pump, dual manifold gauge, leak detector, brazing tools, nitrogen tank, etc.
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Real field experience to handle unexpected challenges (load-bearing walls, structural obstacles, weather conditions, etc.).
At AirGreen, our technicians have years of hands-on experience, and we hold all required licenses and certifications to operate across Greater Montréal.
Grants and savings: what you could miss out on
When working with an accredited company like AirGreen, you’re eligible for various grants, such as:
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The Hydro-Québec LogisVert program (up to $2,172 in rebates).
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Transition énergétique Québec (TEQ) incentives.
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Federal and provincial eco-renovation tax credits.
A DIY installation makes you ineligible for all of these programs.
What we recommend
If you have experience with light electrical and plumbing work, you might be able to assist with prep steps (like cable routing or interior bracket placement), but the final installation must absolutely be handled by a certified technician. Not just for your safety, but to ensure performance, durability, and a strong return on your HVAC investment.
Our commitment at AirGreen
At AirGreen, we proudly serve Montréal, Laval, Longueuil, the North Shore, and the South Shore with a meticulous and personalized approach. Our wall-mounted heat pump installations are guaranteed, eligible for rebates, fully code-compliant, and always performed by experienced, certified technicians.
We support you from A to Z—from helping you select the right unit (brand, BTU, energy efficiency) to complete installation and ongoing annual maintenance. We are committed to transparency, top-tier craftsmanship, and customer satisfaction at every step.